I can only get this to work if i use the web interface deal to pass a BASE64 encoded image such as

{FileData:"blahblahblahbase64codestuff"}

I preprocess an image to base64... sent it over.. and it saved and image was good

But when I try to make my own little test client program, the server blows up with

"Message content is not a valid JSON value."

Can't figure out how to use Tidhttp to post properly to http://localhost:8080/datasnap/rest/TServerMethods1/%22UploadImage%22/
with my data

I guess last thing I'd like to figure out if anyone knows, is how to easily convert a TDataSet to JSON?

Have a routine to kick off a query. And Like to return the results as a plain old JSON if possible.

VAR qInventory : tadoquery;
..
 
aDBXReader := TDBXDataSetReader.Create (qInventory, False );
result := TDBXJSONTools.TableToJSON (aDBXReader, qInventory.RecordCount , False);
..

var qData  : TFDQuery;
     Connection: TFDConnection;
     fStream : tstringstream;
     FDStanStorageJSONLink1: TFDStanStorageJSONLink;
 begin
    FDStanStorageJSONLink1:= TFDStanStorageJSONLink.Create(nil);
   
 Connection := TFDConnection.Create(nil);
    Connection.Params.AddPair('DriverID','ODBC');
    Connection.Params.AddPair('DataSource','MyDB1');
    Connection.LoginPrompt := false;
 
    qData := TFDQuery.Create(nil);
    qData.Connection := Connection;
    qData.SQL.Text := mySQLstr;
    qData.Open;
    fStream := tstringstream.Create;
    qData.SaveToStream(fStream,tfdstorageformat.sfJSON);
    fStream.Position := 0;
    result    := TJSONObject.ParseJSONValue(TEncoding.ASCII.GetBytes(fStream.DataString),0) as TJSONObject;
    freeandnil(FDStanStorageJSONLink1);
    freeandnil(qData);
    freeandnil(fStream);
    freeandnil(connection);
end;